1. Movement into and out of the Cell And Cell Division
Anatomy & Physiology I
Movement into and out of the Cell
And
Cell Division
Instructor: Mary Holman

2. A membrane is permeable to things that can pass through it and
A membrane is permeable to things that can pass through it and impermeable to things that can’t.
The cell membrane is not completely permeable to anything but does allow some substances to pass through it more easily than others - this property is called selective permeability.

3. 4 ways for molecules to pass through the cell membrane
Passive Transport
A. Directly through the phospholipid membrane
B. Through membrane channels
Active Transport
A. Via carrier molecules
B. Via vesicles

4. Simple Diffusion
Fig. 3.20
Time

5. Diffusion Across a Permeable Membrane
Fig. 3.21
Diffusion Across a Permeable Membrane
Permeable
membrane
Solute molecule
Water molecule A B A B A B
(1)
(2)
(3)
Time
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6. Oxygen and carbon dioxide move
down the concentration gradient by diffusion
Fig. 3.22
High O2
Low O2
High
CO2
Low
CO2
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7. Fig. 3.23 Facilitated Diffusion Fig. 3.23 Region of higher
concentration
Transported
substance
Region of lower
concentration
Protein carrier
molecule
Cell
membrane
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8. Fig. 3.24 Osmosis Fig 3.24 Selectively permeable membrane
Protein molecule
Water molecule A A B B
(1)
(2)
Time
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9. A solution with the same osmotic pressure as physiological conditions
Isotonic solution
A solution with the same osmotic pressure as physiological conditions
Hypertonic
A solution with higher than physiological osmotic pressure
Hypotonic
A solution with lower than physiological osmotic pressure

10. Rbc in isotonic solution
(a)
Rbc in hypertonic solution
Fig. 3.25
(b)
Rbc in hypotonic solution
5,000x
(c)
© David M. Phillips/Visuals Unlimited
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11. Fig. 3.26 Filtration Filter paper Water and solids Solids Water
Gravitational force
Water
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12. Filtration in the Body Capillary wall Tissue fluid Blood pressure
Fig. 3.27
Filtration in the Body
Capillary wall
Tissue fluid
Blood
pressure
Blood
flow
Larger molecules
Smaller molecules
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13. Active Transport Transport against (up) a concentration gradient
Facilitated by a carrier molecule
Requires energy
Fueled by the breakdown of ATP

14. Fig. 3.28 Active Transport Carrier protein Binding site
Region of higher
concentration
Cell membrane
Region of lower
concentration
Active
Transport
Phospholipid
molecules
Transported
particle
Carrier protein
with altered shape
Cellular
energy
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15. Endocytosis Exocytosis Both require energy supplied by ATP
Vesicular Transport
Endocytosis
Exocytosis
Both require energy supplied by ATP

16. Endocytosis
The internalization of substances into the cell by the formation of a vesicle
Pinocytosis - “cell drinking”
Phagocytosis - “cell eating”
Receptor-mediated endocytosis -
Receptor sites select specific substances to be internalized

17. Pinocytosis Fig. 3.29 Cell membrane Fluid-filled vesicle Fluid
Cytoplasm
Nucleolus
Nucleus
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18. Phagocytosis Fig. 3.30 Cell membrane Particle Phagocytized particle
Vesicle
Nucleus
Nucleolus
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19. Receptor-mediated Endocytosis
Molecules
outside cell
Receptor-ligand
combination
Vesicle
Receptor
protein
Cell
membrane
Cell
membrane
indenting
Cytoplasm
(a)
(b)
(c)
(d)
Fig. 3.32
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20. Exocytosis
The externalization of substances from the cell by the formation of a vesicle
Requires energy

21. Fig. 3.33 Secretion via Exocytosis Endoplasmic reticulum Golgi
apparatus
Nucleus
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22. Exocytosis after Phagocytosis
Digestive
products
Vesicle
Residue
Lysosome
Phagocytized
particle
Nucleus
Nucleolus
Fig. 3.31
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23. Transcytosis
Combines receptor-mediated endocytosis and exocytosis to transport particles through a cell

24. Transcytosis Fig. 3.34 HIV-infected white blood cells Anal or
vaginal canal V
iruses bud
HIV
Receptor-mediated
endocytosis
Lining of anus
or vagina
(epithelial cells)
Exocytosis
Cell
membrane
Receptor-mediated
endocytosis
Fig. 3.34
Virus infects
white blood cells on
other side of lining
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25. THE CELL LIFE CYCLE
The changes within a cell from the time it is formed until it divides to produce two new identical cells
The cell cycle has two major stages
Interphase
Cell division stage - Mitosis

26. Fig. 3.35 The Cell Cycle Mitotic Phase DNA Replication Fig. 3.35
G2 phase
Mitotic
Phase
Prophase
Interphase
Mitosis
S phase:
genetic
material
replicates
Metaphase
Anaphase
Telophase
Proceed
to division
Cytokinesis
G1 phase
cell growth
Remain
specialized
Restriction
checkpoint
Apoptosis
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27. Interphase The phase between cell divisions
~ 90% of typical cell’s time is spent in interphase
Cells carry out metabolic activities and specialized functions while in Interphase
In addition, while in Interphase, cells prepare to divide
Three stages: G1, S, and G2

28. Late Interphase Fig. 3.36a ~360x Late Interphase Cell has passed the
restriction checkpoint
and completed DNA
replication, as well as
replication of centrioles
and mitochondria, and
synthesis of extra
membrane.
Nuclear
envelope
~360x
Chromatin
fibers
Centrioles
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29. Mitotic Phase of the Cell Cycle
Consists of karyokinesis and cytokinesis
Described in four stages - PMAT
Prophase
Metaphase
Anaphase
Telophase
These events plainly visible under the light microscope

30. Prophase Mitosis Fig. 3.36b ~360x Aster Prophase
Chromosomes condense and
become visible. Nuclear
envelope and nucleolus
disperse. Spindle apparatus
forms.
Microtubules
(b)
Centromere
Spindle fiber
Late prophase
Sister
chromatids
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© Ed Reschke

31. © Biophoto Associates, SPL/Photo Researchers, Inc.
Chromosomes
© Biophoto Associates, SPL/Photo Researchers, Inc.
36,000x
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32. © SPL/Photo Researchers, Inc.
This normal karyotype shows 23 pairs of chromosomes:
Pairs 1-22 are autosomes (they do not determine sex) Pair 23 are the sex chromosomes
Pg. 909 1 2 3 4 5 6 7 10 8 9 11 12 13 14 15 16 17 18 19 20 21 22 23
Sex chromosomes
(female)
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© SPL/Photo Researchers, Inc. 32

33. Metaphase Mitosis Fig 3.36 c ~360x Metaphase Chromosomes align along
equator, or metaphase plate
of cell.
© Ed Reschke
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34. Anaphase Mitosis Fig. 3.36d ~360x Anaphase
Sister chromatids separate to
opposite poles of cell. Events
begin which lead to cytokinesis.
© Ed Reschke
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35. Mitosis - Telophase and Cytokinesis
~360x
Chromosomes
Nuclear
envelopes
Telophase and Cytokinesis
Nuclear envelopes begin to
reassemble around two daughter
nuclei. Chromosomes decondense.
Spindle disappears. Division of
the cytoplasm into two cells.
© Ed Reschke
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36. Early Interphase Fig. 3.36e Early Interphase of daughter cells—
a time of normal cell
growth and function.
Cleavage
furrow
(e)
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37. 5,100x
Pg. 83

38. Control of Cell Division
Number of divisions dependent on cell type
Telomeres
Contact density
Genetic control
tumor suppressor gene
oncogenes
Apoptosis
Loss of control of cell division leads to tumors/cancer

39. Cell Differentiation Fig. 3.40 Self- renewal Stem cell
(hematopoietic stem cell)
Stem cell
Progenitor cell
(e.g., myeloid progenitor cell)
Specialized cells
(white blood cells)
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40. Cell Death Fig. 3.42 Death receptor on doomed cell
binds signal molecule. Caspases
are activated within.
Caspases destroy various
proteins and other cell components.
Cell becomes deformed.
Blebs
Cell fragments
Phagocyte attacks
and engulfs cell
remnants. Cell
components are
degraded.
© Peter Skinner/Photo Researchers, Inc.
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